An invention in which restriction of the functions of an image processing apparatus, the use of the functions of which is restricted is cancelled with a canceling key including an encrypted manufacture number of the apparatus for managing the functions of the apparatus is disclosed in Japanese Laid-Open Patent Publication No. 2001-309099. This image processing apparatus is implemented as a digital multi-function printer and the like. Extension of functions after shipment can be quickly implemented at a low cost. A main program which controls basic operations of the copying machine, printer and facsimile and a subprogram which controls additional operations of a network scanner when it is accessed in the main program are stored. If a user purchases an additional function package and transmits the manufacture number of the image processing apparatus and ID information of the purchased additional function package to a management apparatus, the management apparatus returns a cancellation key of encrypted manufacturing number. The returned cancellation key is decrypted by a control unit. If the decrypted number corresponds with the content of a storage unit, the access is enabled. Therefore, even after shipment, function extension can be quickly achieved at a low cost without exchanging circuit boards and/or memories.
In a method in which the restriction of the functions of conventional information processing apparatus is cancelled with a canceling key which is generated by using information specific to the information processing apparatus, the canceling key corresponds to the information processing apparatus in a one-to-one relationship. When the information processing apparatus is replaced with new one due to malfunction, there is a problem that the purchased function can not be transferred to new information processing apparatus even if the user paid for new function.